Caro is back, and the obsession goes on

“I get letters, constantly, saying, `I see your book’s coming. I hope you’re going to prove in this book that LBJ did it,’” the award-winning and ongoing biographer of Lyndon Johnson says during a recent interview at his midtown Manhattan office. “Did it,” as in killed President Kennedy.

“When I talk at colleges, you can hardly have a lecture or a speech without one of the first questions being, “Are you going to prove that Johnson did it? Or, are you going to show that Johnson was involved in it?’ And when you say Johnson had nothing to with it. You can feel the audience doesn’t accept it. You lose your audience.”

Believers in Oliver Stone’s “JFK” and other conspiracy theorists who hoped that Caro, the most hard-working of historians, would finally nail Johnson will have to look elsewhere. In “The Passage of Power,” the fourth of five planned volumes on Johnson, Caro devotes more than 100 pages to the events immediately before, during and after Nov. 22, 1963. Nothing in his many years of research made him suspect Johnson.

“I never came across a single hint, in anything I did _ in interviews or all the documents _ that would lead you to make such a conclusion,” he says.

The Johnson books are an obsession, regardless of who you blame for the death of JFK. Caro has been writing about the late president for nearly 40 years and fans, as anxious in their own way as followers of “Harry Potter,” have waited a decade for the latest volume. “Passage of Power” begins in 1958, when Johnson is considering a presidential run; continues through his unhappy time as vice president; and ends in early 1964, weeks after he succeeds Kennedy.

Published this week, the new book is around 700 pages and the series totals more than 3,000; Caro has enough unused material in his filing cabinets to fill many more. Length has not deterred readers or critics. The first three volumes have sold more than 1 million copies. Caro has won two National Book Critics Circle awards, a National Book Award and a Pulitzer Prize, for “Master of the Senate.” More honors seem likely for “Passage of Power,” which The New York Times’ Michiko Kakutani has praised for its “consummate artistry and ardor.”

But his influence reaches beyond sales and prizes. The author, who has never held or sought political office, has become a kind of wise man in Washington. According to Ron Suskind’s best-selling “Confidence Men,” Democratic senators read Caro’s books as they attempted to pass health care legislation in 2009 and Rep. Barney Frank consulted “Master of the Senate,” which covered Johnson’s dominating run as Senate majority leader, as he urged fellow Democrats to support new financial regulation. President Obama has met at the White House with Caro and has said that “The Power Broker,” Caro’s Pulitzer winner about municipal builder Robert Moses, influenced his own political thinking.

Caro said he hears often from members of Congress. He remembers being asked to visit by Sen. Edward Kennedy’s staff several years ago, when Republicans, then in the majority, were threatening to change long-established rules on debate and streamline the voting process. Some called it “the nuclear option,” and it was never enacted.

“I think everyone was reading `Master of the Senate,’” says former Kennedy aide Jim Flug, who helped arrange Caro’s visit and adds that the historian may have persuaded a couple of legislators to change their minds. “Whenever Bob comes to Washington _ I remember a breakfast at the Library of Congress _ all the events are always full up. You have people in Washington just listening to every word he says.”

Room for the new book already is being made in current political debate. Caro mentions a review in Newsweek by David Frum, a contributing editor for the magazine and former speechwriter for President George W. Bush. Frum greatly admired “Passage of Power” and called it a primer for how a president might lead. He then labeled it an “unspoken critique of President Obama.”

“Yes, certainly, Obama shares Lyndon Johnson’s gift for driving opponents crazy, if it is a gift,” Frum writes. “But the use of power Caro so vividly describes is not something that comes naturally to our current president.”

Ridiculous, Caro responds. Any critique is not only unspoken, but “unwritten,” “unthought.”

“I have a high opinion of Obama,” says Caro, praising the president for the health care bill and other legislation.

For Caro, lean and determined at age 76, a sign of achievement is when someone complains about his work. His success rate is high. Johnson aides and family members were angered by his early books on LBJ, especially the second volume, “Means of Ascent,” which presented Johnson as vicious and unprincipled as he won a highly questionable Senate race in 1948. But “Master of the Senate” was a redemptive book for both subject and biographer and Caro was welcomed, for the most part, by the Johnson camp. One of his toughest critics, former LBJ aide Jack Valenti, agreed to talk to him for future volumes. The Lyndon Baines Johnson Library and Museum, in Austin, Texas, no longer restricted his access and even began selling his books.